1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to effectively constructing data transmission channels in an extended wireless local area network (LAN) architecture constructed with inter-communicating mobile nodes.
2. Description of Related Art
A wired network includes relays having both wire and wireless interfaces in order to transmit data to mobile nodes connected to a wireless network. In the IEEE 802.11 standard, access points (APs) operate like a relay in a wireless LAN. As shown in FIG. 1, AP1 130 and AP2 140 are connected to the Internet 100 through a router 110. AP1 130 and AP2 140 receive a frame having a media access control (MAC) address, that is, a link layer address from the Internet 100 or a host 120 through a wired network and forwards the frame to stations (STAs) 150, 160, 170, and 180, that is, the mobile terminals included in a basic service set (BSS) according to the MAC address. In general, a range of the BSS is determined based on a wave approaching distance (coverage range) of the AP. In some cases, like in the case of STA3 170, two or more ALP coverage ranges may overlap, so that there may be a mobile station capable of receiving a transmission from two or more APs. In this case, according to the IEEE 802.11 standard, BSSID is used for all the STAs to be wireless-linked to one AP and receive and transmit the frame from and to the one AP.
However, the IEEE 802.11 standard does not apply to a recently-developed extended wireless LAN architecture wherein a mobile node can route a frame in a wireless manner, like in a wireless mesh network which is separated from the wired network. In the extended wireless LAN architecture, the mobile nodes can receive and transmit frames therebetween in a wireless manner, so that an ad-hoc network can be constructed. Therefore, there is a problem of broadcast storm in which broadcasted frames are repetitively transmitted along a loop in the extended wireless LAN architecture. In addition, the repetition along the loop may be blocked by using a method re-constructing a topology such as spanning tree. However, the method has a problem in that the frame transmission connection channel is inefficiently constructed.
In addition, when the frame is transmitted through the wired network to the mobile node, which can communicate with two or more portals (transmission points connecting the wired network with the wireless network), the extended wireless LAN architecture does not clearly specify which AP forwards the frame.